In the related art, a technique is known which displays a subject stereoscopically by using a pair of images obtained by capturing the same subject from different viewpoints (see, for example, PTL 1).
For example, in the case of a typical camera, a subject is captured in a state in which the optical axis of the camera is substantially horizontal to the ground, and the obtained image is projected onto a screen that is perpendicular to the ground. In this case, it can be supposed that the viewpoint position of the user who sees the displayed image is located on a straight line that is substantially perpendicular to the screen on which the image is displayed.
Consequently, when an image is to be displayed stereoscopically with such a display system, the binocular disparity/parallax of the user is expressed as a shift of the image to the left and right. That is, the subject is displayed stereoscopically by use of a pair of images having a disparity in a direction which is perpendicular to the user's sight line direction and along which the user's left and right eyes are arranged.